The document discusses different methods of speed control for DC motors using static ward Leonard drive systems. It describes single phase and three phase fully or half controlled rectifier configurations that provide variable DC voltage to the motor, allowing control in one or two quadrants. Low power applications typically use a single phase fully controlled rectifier while high power uses three phase. The systems can operate in continuous or discontinuous conduction modes to control motor speed and torque characteristics.

1. ED&C – Speed control
methods of DC Motor_Static
ward Leonard Drive
BY
P.KARTHIKEYAN/AP/EEE/KEC

2. Static ward Leonard Drive
• Controlled rectifier – Variable DC voltage
• Also known as Controlled rectifier fed dc drive
• 1Φ and 3Φ fully controlled rectifier provide DC voltage in either
direction, so it allows motor control in quadrant I and IV
• 1Φ and 3Φ half controlled rectifier provide DC voltage in oe direction,
so it allows motor control in quadrant I
• Low power application - 1Φ fully controlled rectifier
• High power application - 3Φ fully controlled rectifier
2

3. Single phase fully controlled converter fed DC
Motor
33

4. Single phase fully controlled converter fed DC
Motor
44

5. Single phase fully controlled converter fed DC
Motor
55

6. Single phase fully controlled converter fed DC
Motor
66

7. Vs
απ +
βα π
β
απ +
βα π
β E
1 2TT
TT 43
απ +
α
IV aa
tω
tω
tω
tω
Discontinuous conduction mode

8. Discontinuous conduction mode
8

9. 9
Discontinuous conduction mode

10. Two Quadrant operation
of the drive
10
Speed torque
characteristics

11. Single phase Half controlled converter fed DC Motor
1111

12. Single phase Half controlled converter fed DC Motor
1212

13. Single phase Half controlled converter fed DC Motor
1313

14. Vs
απ +
βα π
β
απ +
βα π
β E
1 2TT
TT 43
απ +
α
IV aa
tω
tω
tω
tω
Discontinuous conduction mode

15. Discontinuous conduction mode
15

16. 16
Discontinuous conduction mode

17. One Quadrant operation
of the drive
17
Speed torque
characteristics

18. Three phase fully controlled converter fed DC
Motor
1818

19. 19

20. 20
Continuous conduction mode

21. 21
Speed torque characteristics

22. 22
Three phase supply
Dual Converter
A B
VA VB
L1
L2
Three phase supply

23. Chopper control of separately excited DC motor
23
VA
ia1
ia2
va
Ia
va
Ia
ton T ωt